Review hospital discharge diagnoses of infants for the period of 7/1/78-12/31/79 by using CPHA/PAS, CHAMP, and other likely sources to identify infants who suffered metabolic hydrochloremic alkalosis while exposed to chloride deficient Neo-Mull-Soy or Cho-Free diets. Identify a sample of children who were exposed to chloride deficient Neo-Mull-Soy or Cho-Free diets in 1978 and 1979 without metabolic hypochloremic alkalosis. Determine long-term outcomesof infants with hypochloremic metabolic alkalosis as a result of exposure to these chloride-deficient formulas and also of children exposed to these formulas who either did not have hypochloremic metabolic alkalosis or in which such documentation is lacking. The outcomes assessed may include physical growth and development, dentition, gross and fine motor development, neurological competence, cognitive development, learning, school achievement, speech development, anduse of language. The outcome measures selected should be justified by citing specific hypoThesis to be tested.